ABSTRACT
Successful early intervention in children with permanent hearing loss requires assessment techniques that can accurately reflect the behavioral audiogram in infancy. This retrospective study compared auditory steady-state response (ASSR) findings from subjects tested in the first three months of life with subsequently obtained behavioral hearing levels. ASSR audiograms were established using amplitude and frequency modulated tones at octave frequencies (500 Hz to 4 kHz). Results obtained from 575 subjects including 285 with normal hearing, 271 with sensorineural hearing loss, and 19 with auditory neuropathy-type hearing loss are presented. ASSR and behavioral hearing thresholds for subjects in the normal and sensorineural groups were highly correlated, with Pearson r values exceeding 0.95 at each of the test frequencies. In contrast, ASSR thresholds in children with AN-type hearing loss did not accurately reflect the behavioral audiogram. Overall, the findings indicate that ASSR testing can offer useful insights into the hearing acuity of children tested in infancy.
Subject(s)
Auditory Diseases, Central/physiopathology , Auditory Threshold/physiology , Evoked Potentials, Auditory, Brain Stem/physiology , Hearing Loss, Sensorineural/physiopathology , Acoustic Stimulation , Audiometry, Pure-Tone , Auditory Diseases, Central/congenital , Auditory Diseases, Central/diagnosis , Auditory Pathways/physiopathology , Child, Preschool , Electroencephalography , Female , Hearing Loss, Central/congenital , Hearing Loss, Central/diagnosis , Hearing Loss, Central/physiopathology , Hearing Loss, Sensorineural/congenital , Hearing Loss, Sensorineural/diagnosis , Humans , Infant , Infant, Newborn , Male , Neonatal Screening/methods , Regression Analysis , Retrospective StudiesABSTRACT
OBJECTIVES: The purpose of this study was to examine the effects of profound auditory deprivation and its treatment by cochlear implantation and stimulation on the metabolic activity of the central auditory system in fetal sheep. METHODS: Six ovine fetuses at 85% to 90% gestation were bilaterally deafened by kanamycin perfusion and unilaterally implanted with cochlear electrode arrays. Half of the implanted animals were stimulated with an extrauterine sound processor, and half were not. Four animals served as hearing controls. One week postoperatively, central nervous system metabolic activity was evaluated in ambient laboratory noise by quantitative autoradiography using (14)C-deoxyglucose. RESULTS: Kanamycin perfusion deafened all treated animals as verified by auditory brainstem response and scanning electron microscopy. Glucose utilization in the inferior colliculus was markedly lower in deafened and unstimulated animals relative to hearing controls. Glucose utilization in implanted-stimulated animals was similar to normal controls. CONCLUSIONS: Changes in central auditory system metabolic activity associated with congenital deafness may be minimized by prompt auditory habilitation.
Subject(s)
Auditory Diseases, Central/metabolism , Auditory Diseases, Central/surgery , Cochlear Implantation , Disease Models, Animal , Fetal Diseases/metabolism , Fetal Diseases/surgery , Prenatal Care/methods , Animals , Anti-Bacterial Agents , Auditory Diseases, Central/chemically induced , Auditory Diseases, Central/congenital , Auditory Diseases, Central/diagnosis , Autoradiography , Brain Chemistry , Carbon Radioisotopes/metabolism , Evoked Potentials, Auditory, Brain Stem , Fetal Diseases/diagnosis , Gestational Age , Humans , Infant, Newborn , Kanamycin , Microscopy, Electron, Scanning , Neonatal Screening , SheepABSTRACT
Recent evidence from individuals born with a profound musical impairment suggests that the ability to process pitch information is normally present from birth. This finding supports the idea that the perception and appreciation of music, both of which critically depend on pitch processing, have a biological basis in the brain.
